Dual Nature of Radiation and Matter - Result Question 49
51. A photosensitive metallic surface has work function, $h v_0$. If photons of energy $2 h v_0$ fall on this surface, the electrons come out with a maximum velocity of $4 \times 10^{6} m / s$. When the photon energy is increased to $5 h v_0$, then maximum velocity of photoelectrons will be
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======= ####51. A photosensitive metallic surface has work function, $h v_0$. If photons of energy $2 h v_0$ fall on this surface, the electrons come out with a maximum velocity of $4 \times 10^{6} m / s$. When the photon energy is increased to $5 h v_0$, then maximum velocity of photoelectrons will be
c3eec34ec6b1fad69db54a20ad4b2dca40c2aa54 (a) $2 \times 10^{7} m / s$
(c) $8 \times 10^{6} m / s$
(b) $2 \times 10^{6} m / s$ [2005]
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Answer:
Correct Answer: 51. (c)
Solution:
- (c) We know that
$h v-\phi=K _{\max }=\frac{1}{2} m v _{\max }^{2}$
According to question
$\frac{5 h v_0-h v_0}{2 h v_0-h v_0}=\frac{v_2^{2}}{v_1^{2}}$
$v_2=2 v_1=2 \times 4 \times 10^{6}=8 \times 10^{6} m / s$.
